<?php
/**
  * wechat php test
  */
//define your token

define("TOKEN", "weixin");

$wechatObj = new wechatCallbackapiTest();
$wechatObj->responseMsg();
$wechatObj->valid();
    # code...



//$wechatObj->valid();

class wechatCallbackapiTest
{
public function valid()
    {
        $echoStr = $_GET["echostr"];
        //valid signature , option
        if($this->checkSignature()){
            echo $echoStr;
            exit;
        }
    }

public function responseMsg(){
    //get post data, May be due to the different environments
    $postStr = $GLOBALS["HTTP_RAW_POST_DATA"];

      //extract post data
    if (!empty($postStr)){
                
        $postObj = simplexml_load_string($postStr, 'SimpleXMLElement', LIBXML_NOCDATA);
        $fromUsername = $postObj->FromUserName;
 
        $toUsername = $postObj->ToUserName;

        $keyword = trim($postObj->Content);
        
        $time = time();
        $textTpl = "<xml>
<ToUserName><![CDATA[%s]]></ToUserName>
<FromUserName><![CDATA[%s]]></FromUserName>
<CreateTime>%s</CreateTime>
<MsgType><![CDATA[%s]]></MsgType>
<Content><![CDATA[%s]]></Content>
<FuncFlag>0</FuncFlag>
</xml>";             
            $msgType = "text";
            $contentStr = "http://ldl.isaphp.com/joinTable.html";
            $resultStr = sprintf($textTpl, $fromUsername, $toUsername, $time, $msgType, $contentStr);
            echo $resultStr;
        }
}

private function checkSignature()
{
        $signature = $_GET["signature"];
        $timestamp = $_GET["timestamp"];
        $nonce = $_GET["nonce"];
       
        $token = TOKEN;
        $tmpArr = array($token, $timestamp, $nonce);
        sort($tmpArr);
        $tmpStr = implode( $tmpArr );
        $tmpStr = sha1( $tmpStr );
            if( $tmpStr == $signature ){
                return true;
            }else{
                return false;
            }
        }
}

?>